1. Field of the Invention
The present invention relates to a jet nozzle for the cooling operations employed in continuous casting plants and in particular for the cooling of the support and guide rollers with liquid or liquid-gas jets, where two or more jet channels are disposed next to each other, where the axes are parallel with respect to each other, where the hydraulic diameter of the nozzle channels is in the area of about 1.5 to 4 millimeter, and where the jet exiting out of the nozzle channels is guided by a guide surface.
2. Brief Description of the Background of the Invention Including Prior Art
A nozzle of the general kind recited above is known from the Austrian Patent AU-PS No. 327,418. This jet nozzle serves primarily for the the cooling of a strand and/or of support and guide rollers in a continuous casting plant.
There is the desire to cast with continuous casting plants strands over a width region which is as large as possible. For example, it is already possible to cast slabs with a width of 2.5 meters. In the case of billet or respectively bloom continuous casting plants the desire is in the direction of being able to cast several strands with billet or, respectively, bloom cross-section, which are neighboring together as close as possible. For example it is the use with a slab cross-section continuous casting plant to cast simultaneously several strands with bloom cross-section instead of the slab cross-section.
It is desirable in the case of plants of this kind to avoid the direct spraying of the closely spaced neighboring strands. In contrast the cooling medium is intended to primarily to pick up the radiation heat of the strand. A particular problem is posed by the edge spraying of the edges of the strand with cooling agent, which is to be avoided if possible, since otherwise the product quality is lowered and a waste disposal of the strand or, respectively, the strands may become necessary. In case of a simultaneous casting of several strands with bloom cross-section at a slab continuous casting plant it is very difficult, to guide the billets on a side, such that a side spraying with cooling agent can result in a sideways migration of a strand.
In case the cooling agent is primarily sprayed against the support and guide rollers, then the problem results that in case of continuous casting plants, which are constructed for the continuous casting of vary wide slabs, that at the more than once over their length supported roller where the jacket is interrupted, cooling agent is sprayed to the faces directed vertically to the axes and is guided from there to the strand.
At plants of usual construction with rollers supported at several points of their length, it was hitherto not possible to avoid that a large percentage of the cooling agent in this manner passed to the strand surface, which was a disadvantage for the quality of the strand or, respectively, the further processing (hot processing or direct use in a rolling mill).